USRE7779E - Improvement in the manufacture of enameled iron-ware - Google Patents

Description

'as according to the length of the UNITED STATES PATENT QFFICE.

FREDERICK G. NIEDRINGHAUS AND WILLIAM F, NIEDRINGHAUS, OF

ST. LOUIS, MISSOURI.

IMPROVEMENT IN THE MANUFACTURE OF ENAMELED IRON-WARE.

Specification forming part of Letters Patent No. 177,953, dated May 30, 1876; Reissue No. 7,119, dated J u1y-3, 1877; application filed September 28, L876.

To ull whom it may concern:

Be it known that we, Fnnnnnrcx G. Nuannmonxus and WILLIAM F. NIEDBINGHAUS, residents of the city of St. Louis, State of Missouri, have invented a new and useful improvement in Enameling Iron-Ware, of which the following is afnll, clear, and exact description:

The present invention relates to an impro'e ment in enameling sheet-iron were, by means whereof a beautifully mottled and more durable enamel is obtained. We do this by causing an oxidation of the metallic base during the enameling process. The preferable way of doing this, in practice, is by omitting the washing of the metal in the alkaline bath afler it has, for the purpose of cleansing it, been immersed in the acid bath, and by utilizing the acid which forms an element in the 'enameling-glaze to oxidize the metal.

The procedure, more particularly described, is as follows: The metal is cleaned, in the usual way, in an acid bath; then, without employing an alkali bath, it is, after the usual scouring to remove the scale, placed in clear water, and allowed to remain, say, at least, half an hour, and so as to remove the acid. "As soon as it taken from the water it is immediately coated with a liquid glaze and placed in the drying-room, where the glaze is slowly dried thereon.

The appearance and characterof the en amel are determined during this drying of the glaze, time taken in the drying, and to the temperature of the drying-room, will be the amount of oxidation.

Nodellnite rule can be given for either-as the processis affected by many circumstancesas, for instana phere. The ware must' be carefully watched during the. process, and the temperature and time regulated by the appearance of the ware. We prepare our glaze from the ordinary 'ingredients, taking care to have the ingredients mixed and thoroughly smelted together in bulk to expel all carbon and other elements that would impede oxidation, and in order that the acid in theglaze may have free action. They are then ground in water and applied in the usual way.

the humidity of the atmosi Now, by reason of the presence of the acid of the glaze, an oxidation of the met-allic base takes place freely during the drying process, and appearing in and throughout the glaze as reddish spots. This causes the enamel, when it is finally formed in the usual way by baking the ware in the oven, to assume the de- I sired mottled appearance. By reason of this oxidation the enamel, also, is caused to enter the pores of the iron, and become more intimately incorporated with the metal, thus renedering the enamel more durable.

To illustrate more clearly our process'we will give the exact formula of the glaze with which acertain batch of our ware was enameled, and the mode of preparing and applying the glaze, not intending, however, to contlne our-- selves to. the precise quantities named in the formula, or to the exact times and temperatures specified in connection with the various steps in the application of the glaze, but simply to show clearly how our result can be obtained.

We took of pure silica,one hundred pounds; of nitrate of soda, ten pounds; of carbonate of soda, thirty pounds; of carbonate of potassa, ten pounds; 0t borax, fifty pounds; of

manganese, eight pounds. All these ingredients were mixed and thoroughly smelted, as above ,stated, and then ground in water for ten hours, adding the usual proportion of clay-in this instance six pounds. This constituted the glaze, in which the iron. goods, pre'parjd asabove specified, were dipped. When the goods were" taken from the glazehath they were at once placed in the dryingroom,(where a temperature of 125 Fahrenheit was maintained,) and allowed to remain there about four hours, when they were thoroughly dried. They were then placed in the baking-oven for about eight minutes, the oven meanwhile being at the ordinary temperature.

This produced a mottled enamel of a brownish appearance. The color, however, may be changed at pleasu -as, for instance, to produce a mottled enamel of-a bluish tint, we would substitute two pounds of oxide of cobalt 'in placeof the manganese; and to produce awhite tint anyof the coloring agents known to enamelers may be used, for our processi does not preclude the use of any of the coloring agents.

Another way-0t measurably accomplishing these ends, when the use of the ordinary alkali bath is retained, is by increasing the" quantity of the boracic, and lessening the alkaline fluxes in the composition of the glaze, snflicient to overcome the alkali and oxidize the metal; and-the character of the mottlin g .is'afleeted by the amount of acid present in the glaze when applied to the were; also, if a mottlin'g of smaller spots is desiredyive increase the horaeic and lessen the alkaline fluxes in the glaze, as the size of the spots will be determined by the amount of acid in the glaze, or upon the freedom with which the acid is allowed to act.

What we claim is- 1. The herein-described process of enameling iron-ware hy'oxidiziug the "iron during the process of drying the glaze, substantially .as set forth.

2. As a new manufacture mottled enameled sheet=iron ware,havingtheoxidized base fused with the surface-glaze.

F. G, NIEDRINGHAUS. 'WM. F; NIEDRINGHAUS. Witnesses:

SAML. S. BOYD,

CHAS. D. MOODY.